Chapters 1 to 5 combined with Lecture notes

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Department
Psychology
Course
PSYB51H3
Professor
Matthias Niemeier
Semester
Summer

Description
Irene Manlegro Summer 2013 PerceptionCognitionChapter 1 IntroductionSensationPerceptionAbility to detect an act sensationand give it a meaning perceptionIf our mental life relies on info from our sense then the place to study these senses is win the sci of HBpsych but not exclusively sto Idea that our perceived reality depends on what our sense pick up was recognized 1 by C18th Etienne Bonnot de Condillac 17151780Exemplifiedimagine mental life of statue w no senses Then allow it to smell Thus its mental life consists of that smell With more sense and EXP its mental life develops Methods To Study Senses 1 Thresholds aThe smallest detectable change of a stimulus Eg how much louder must one turn up the radio for one to notice a change in volume 2 ScalingMeasuring private experiences a Quale pl Qualia in philosophy a private conscious experiences of sensation or perceptioni Experiences 3 Signal detection theory a psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise a Measures obtained from a series of presentations are sensitive and criterion observers threshold Eg yes I hear that no I dont of the observer 4 Sensory Neuroscience explain how your perception of the world depends on the activity of our sensory nerces at least as much as it depends on the world itself 5 Neuroimaging methods of itseeing how the brain works when we experience stimuli1 Thresholds and the Dawn of Psychophysics Perceptions focus what is real Eg Morpheus from Matrix What does early philosophy teach us about perceptionMorpheus was realPlatoAllegory of the cavemetaphor for our perception o Prisoners born in cavechained faced to wallonly see shadows thats cast indirectly by fireWhat they perceive is limited and they cant see moreSugg Our perception depends on our senses and so is limited Reality is thus richer than what we see bc of these restrictionsBecause sense evolved to environment there are some skills that dont matter to us o Perception and senseevolution survival eg venus fly trap o Importance of type of energy in environment that is needed determines which sense will evolveFor venus fly trap their energy stems from flies So their sense of touch evolved in order for them to trap the flies otherwise they wont have food Humans sense of touch is important too but our main sense is vision So having the fly traps ultrasensitive touch is a little bit pointless for us o Other animal examplesBee See ultraviolet lights to sense colourful flowers Snake Infrared light w tongueeat mice We dont have same special need for this skillDog Keen ear and nosecommunicate via markings We dont need this because we have visionEcholocation Dolphinssound signals for huntingNot in H can be learned if constantly underwater bc were fine with vision What alters perceptionHeraclitus 540480 BCEcant step in same river twiceEverything flows o Each events perceived differently each time o Upon seeing you learn so the same experience is different every time you experience itExperience and learning o What you see first biases our perception Eg slide w mouse vs man group1 who was exposed to the mouse first said the third picture which is a combination of both the mouse and man is a mouse where group 2 who were exposed to the man picture argued its a manAdaptation o If something is the same we adapt to it Irene Manlegro Summer 2013 PerceptionCognition o Vision eg slide 11 eyes adaot to slight colour changesdifferences and eliminate this difference so both sides look the same example of colour adaptationChange o Our system picks out changeso Consciousness has to do w changesDemocritus 460370 BCEmade concept of atoms o The worlds made up of atoms that collide o Contrast to platoSensations are caused by atoms leaving objects and making contact w sensesThus what we sense IS real and not an illusion They arent shadows because were interacting w itPerceptions a result of physical interaction bw world and our bodySensory transductor A receptor that converts phys energy from environment into neural activityNativism and Empiricism Nativism The idea that the mind produces ideas that arent from external sourcesPlato nativist truest sense of reality from ppls minds and souls o Ideas had to do w something beyond perception outside cave Something else besides bodyStates knowledge is born win you hence Plato nativisimborn w you Dualism Have 2 sep entities mindbodyMind exists separately from the material world of the body2 entities win universe egspiritsoul mattermind Descartes 15961650 is most famous for this view Monism mindmatter are formedreducable to 1 single substance or principle of beingOpposite dualismPhysical matteronly realitytype of materialismEverything eg mind expl by matterphysical phenomenonNo soul thus born wout nativism Empiricism knowledges from EXK 1 Hobbes believed this 2 Locke wanted to expl how we get knowledge from EXP Psychophysics Science of defining quantitative relationship bw physical and psychological subj eventsGustav FechnerInvented psychophysics o German scientistphilosoper18011887considered true founder of experimental psych though the titles Wilhem Wudt o Tried to reconcile all opposing views interested in relationship bw mind and matter placing him bw dualim and Materialism o Argued Pansychism all matter aliveinanimate has consciousness o If all matter has consciousness then it must be possible to quantify itfind laws o Goal relationship bw sensation mindenergy matter that gave rise to sensation Called this psychophysicspsychomind physics matter o Fechners law a principle describing the relationship bw stimulus and resulting sensation that says the magnitude of subjective sensation increases proportionally to the logarithm if the stimulus intensitySk log R Spsych sensation which isto logarithm of psych stim lvl log R X constant k mathematical expression that demonstrates relationship bw psyche and physics hence psychophysicsway to think of mindmatterWebber interested in touch o Dscovered smallest change in stimulus eg weight of an obj that can be detected is consistent proportion of stimulus lvlLighter standart weightbetter at detecting small diff bc larger standardlarger diff for diff to be detectedHence Just noticeable diff JND smallest detectable diff dw 2 stimuli or min change needed to be correctly detectedo webbers Law The principle describing the relationship bw stimulus and resulting sensation that says the JND just noticeable diff is a constant fraction of the comparison stimulus o Webers fractionEg this example is JND Irene Manlegro Summer 2013 PerceptionCognition2 point threshold the minimum distance at which 2 stimuli eg 2 simultaneous touches are just perceptible as different Absolute threshold Minimum amount of stimulation necessary for a person to detect a stimulus 50 of the t Examples Ticking watch thresholds expressed in distance cm between the watch and ones ear before its audible how close it has to be in order to perceive it o JNDmove it from one distance to another and ask if someone can notice if it has changed positions Then measure the distance at which they canLight Absolute thresholdincrease or decrease the brightness and measure how much more it had to increase or decrease for one to seenot perceive ito JND measure the difference in brightness needed before someone notice the light has dimmed or gotten brighterFace perception absolute thresholdemotional expression at which point can one perceive a smile gender how much change is needed in order for a face to look MF Difference bw absolute threshold and JNDAbsolute threshold measures how strong a stimulus has to be to be detectable where as JND takes the stimulus and measures how much stronger or lessit has to be in order for someone to JUST NOTICE and change of the stimulusPsychophysical Methodsby fetchnerMethod of constant stimuliYou create many stimuli w diff intensities to find the smallest detectable intensity A psychological method in which many stimuli ranging from rarely to almost always perceivable or rarely to almost always perceivably different from a reference stimulus which are presented one at a time Participants respond to each presentation yn or samediff o Can measure both absolute thresholds or JND depending on your experiments design Qsref slide 39 Ticking watch example Test whether the distance at which they can or cant hear Test this distance multiple times We cant go worse than 0 because we cant be worse than hearing it Cant go about 100 because you cant hear it more Its an S shape because Hvariabilityo Method of constant stimuli because each stimulus level is constant and tested again and againOne measure isnt enough since subtle perceptual jugements threshold judgements are variable so you must test it multiple times to get the avgThe intenstity needed to detect a stimulus 50 of the timethresholdMethodinefficient bc much of subjects time can be spent w stimuli that are clearly well above or below threshold Method of limits more efficient that constant stimuliA psychophysical method in which the particular dimension of a stimulus or the diff bw 2 stimuli is varied incrementally increases gradually till the participant responds differentlyTicking watch exampleStart either far distance or close then move closeaway and ask at different distances if they hear it more or less The line right that cuts bw Y and N draws the thresholdMethod of adjustmentMethod of limits in which the subject controls the change in the stimulus
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